scholarly journals A log-normal spectral analysis of inorganic grain-size distributions from a Canadian boreal lake core: Towards refining depositional process proxy data from high latitude lakes

Sedimentology ◽  
2017 ◽  
Vol 64 (3) ◽  
pp. 609-630 ◽  
Author(s):  
Paul R. Gammon ◽  
Lisa A. Neville ◽  
R. Timothy Patterson ◽  
Martine M. Savard ◽  
Graeme T. Swindles
Keyword(s):  
Grain Size ◽  
Spectral Analysis ◽  
High Latitude ◽  
Size Distributions ◽  
Proxy Data ◽  
Boreal Lake ◽  
Depositional Process ◽  
Grain Size Distributions ◽  
Log Normal ◽  
Lake Core

Tail Departure of Log-Normal Grain Size Distributions in Synthetic Three-Dimensional Microstructures

2011 ◽  
Vol 43 (8) ◽  
pp. 2810-2822 ◽  
Author(s):  
Joseph C. Tucker ◽  
Lisa H. Chan ◽  
Gregory S. Rohrer ◽  
Michael A. Groeber ◽  
Anthony D. Rollett
Keyword(s):  
Grain Size ◽  
Three Dimensional ◽  
Size Distributions ◽  
Grain Size Distributions ◽  
Log Normal

scholarly journals Depositional Process and Landform of the Kiso River Delta, Reconstructed from Grain Size Distributions, and Accumulation Rate of Sediment Cores

2005 ◽  
Vol 44 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Masaaki Yamaguchi ◽  
Toshihiko Sugai ◽  
Osamu Fujiwara ◽  
Hiroo Ohmori ◽  
Takanobu Kamataki ◽  
...  
Keyword(s):  
Grain Size ◽  
Accumulation Rate ◽  
Sediment Cores ◽  
River Delta ◽  
Size Distributions ◽  
Depositional Process ◽  
Grain Size Distributions

Study of the Effect of Pinning Particles on Grain Size Distributions

2013 ◽  
Vol 753 ◽  
pp. 361-366 ◽  
Author(s):  
Han Li ◽  
Suk Bin Lee ◽  
Anthony D. Rollett
Keyword(s):  
Grain Size ◽  
Normal Distribution ◽  
Grain Growth ◽  
Volume Fraction ◽  
Medium Size ◽  
Second Phase ◽  
Size Distributions ◽  
Grain Size Distributions ◽  
Log Normal ◽  
Log Normal Distribution

The present paper studies grain growth in the presence of inert particles by performing large-scale simulations using a parallel Monte Carlo Potts model. The effect of the second phase particles on the grain size distribution (GSD) is analyzed. The GSDs diverge markedly from log-normal distribution for normal grain growth case. For the cases with low volume fraction of particles, we find that the grain size distributions approach log-normal as stagnation takes hold. For the cases with a high volume fraction of particles, however, medium-size grains reach the log-normal distribution but both lower and upper tails diverge noticeably from the log-normal distribution over time.

scholarly journals Effect of Strain-Induced Precipitation on the Recrystallization Kinetics in a Model Alloy

2021 ◽  
Author(s):  
Mo Ji ◽  
Martin Strangwood ◽  
Claire Davis
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Avrami Exponent ◽  
Model Alloy ◽  
Size Distributions ◽  
Recrystallization Kinetics ◽  
Grain Size Distributions ◽  
Recrystallized Grain Size ◽  
Nb Addition

AbstractThe effects of Nb addition on the recrystallization kinetics and the recrystallized grain size distribution after cold deformation were investigated by using Fe-30Ni and Fe-30Ni-0.044 wt pct Nb steel with comparable starting grain size distributions. The samples were deformed to 0.3 strain at room temperature followed by annealing at 950 °C to 850 °C for various times; the microstructural evolution and the grain size distribution of non- and fully recrystallized samples were characterized, along with the strain-induced precipitates (SIPs) and their size and volume fraction evolution. It was found that Nb addition has little effect on recrystallized grain size distribution, whereas Nb precipitation kinetics (SIP size and number density) affects the recrystallization Avrami exponent depending on the annealing temperature. Faster precipitation coarsening rates at high temperature (950 °C to 900 °C) led to slower recrystallization kinetics but no change on Avrami exponent, despite precipitation occurring before recrystallization. Whereas a slower precipitation coarsening rate at 850 °C gave fine-sized strain-induced precipitates that were effective in reducing the recrystallization Avrami exponent after 50 pct of recrystallization. Both solute drag and precipitation pinning effects have been added onto the JMAK model to account the effect of Nb content on recrystallization Avrami exponent for samples with large grain size distributions.

Grain Growth in Nanocrystalline Nickel

1999 ◽  
Vol 580 ◽  
Author(s):  
G.D. Hibbard ◽  
U. Erb ◽  
K.T. Aust ◽  
G. Palumbo
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Grain Growth ◽  
Size Distributions ◽  
Nanocrystalline Nickel ◽  
Scanning Calorimetry ◽  
Solute Content ◽  
Grain Size Distributions ◽  
Thermal Stability Of ◽  
Total Solute Content

AbstractIn this study, the effect of grain size distribution on the thermal stability of electrodeposited nanocrystalline nickel was investigated by pre-annealing material such that a limited amount of abnormal grain growth was introduced. This work was done in an effort to understand the previously reported, unexpected effect, of increasing thermal stability with decreasing grain size seen in some nanocrystalline systems. Pre-annealing produced a range of grain size distributions in materials with relatively unchanged crystallographic texture and total solute content. Subsequent thermal analysis of the pre-annealed samples by differential scanning calorimetry showed that the activation energy of further grain growth was unchanged from the as-deposited nanocrystalline nickel.

Holocene sediment transport and climate variability of offshore Adélie Land, East Antarctica

2021 ◽  
Author(s):  
◽  
Anna Borisovna Albot
Keyword(s):  
Grain Size ◽  
Sea Ice ◽  
Ross Sea ◽  
Size Distributions ◽  
Accumulation Rates ◽  
Glacial Meltwater ◽  
The Core ◽  
Grain Size Distributions ◽  
The Antarctic ◽  
Mass Accumulation Rates

<p>Grain size analysis of the terrigenous fraction of a laminated diatom ooze dating back to 11.4 kyr recovered offshore Adélie Land, East Antarctic margin was used to examine variations in sediment transport, depositional environments and Holocene climate variability at the location. Interpretations were assisted by additional proxies of primary productivity (δ¹³CFA, BSi%), glacial meltwater input (δDFA) and subsurface temperature (TEXL₈₆). Three lithologic intervals with distinct grain size distributions were identified. At ~11.4 ka the diatom ooze has a clear glacimarine influence which gradually decreases until ~8.2 ka. During this time interval, coincident with the early Holocene warm period, sediment is inferred to have been delivered by glacial meltwater plumes and ice-bergs in a calving bay environment. It is suggested that the glaciers in Adélie Land had retreated to their present day grounding lines by 8.2 ka, and from then on sediment was delivered to the site primarily via the Antarctic Coastal and Slope Front Currents, largely through a suspended sediment load and erosion of the surrounding banks. Enhanced biogenic mass accumulation rates and primary production at 8.2 ka suggest onset of warmer climatic conditions, coincident with the mid-Holocene Climatic Optimum.  At ~4.5 ka, grain size distributions show a rapid increase in mud content coincident with a transient pulse of glacial meltwater and a sudden decrease in biogenic and terrigenous mass accumulation rates. The increased mud content is inferred to have been deposited under a reduced flow regime of the Antarctic Coastal and Slope Front Currents during the Neoglacial period that followed the final stages of deglaciation in the Ross Sea. It is hypothesised here that cessation of glacial retreat in the Ross Sea and the development of the modern day Ross Sea polynya resulted in enhanced Antarctic Surface Water production which led to increased sea ice growth in the Adélie Land region. The presence of sea ice led to reduced primary production and a decrease in the maximum current strength acting to advect coarser-sized terrigenous sediment to the core site during this time.  Sedimentation rates appear to have a strong correlation with the El Niño Southern Oscillation (ENSO) over the last 8.2 kyr, and are inferred to be related to changing sea ice extent and zonal wind strength. Light laminae counts (biogenic bloom events) appear to decrease in frequency during time intervals dominated by El Niño events. Spectral analysis of the greyscale values of core photographs reveals peaks in the 2-7 year band, known ENSO periods, which increase in frequency in the mid-and-late Holocene. Spectral analyses of the sand percent and natural gamma ray (NGR, a measure of clay mineral input) content of the core reveal peaks in the ~40-60, 200-300, 600, 1200-1600 and 2200-2400 year bands. The most significant of these cycles in the NGR data is in 40-60 year band may be related to internal mass balance dynamics of the Mertz Glacier or to the expansion and contraction of the Antarctic circumpolar vortex. Cycles in the 200-300 and 2200-2400 year bands are related to known periods of solar variability, which have previously been found to regulate primary productivity in Antarctic coastal waters. Cycles in the 590-625 and 1200-1600 year bands have a strong signal through the entire record and are common features of Holocene climatic records, however the origin of these cycles is still under debate between solar forcing and an independent mode of internal ocean oscillation.</p>

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